how to work on pcbs that are thick

[amateur_24]

I am using aoyue 2702A+ rework station. I think the ps5 otherboard is difficult to bring up to temp so I desolder stuff off it.

I have my hot air set at 480 degrees celcius (max) then airflow at 80. I was sat there for several mins butI still couldn't get the mosfet off.
What am I doing wrong?

 

[schmitt trigger]

Could it be defective?
Do you have a thermocouple thermometer to measure the actual airflow temperature?
If not, does the airflow melt solder wire in its stream?

 

[ronsimpson]

My power boards have very thick coper. Many layers. Most layers are 90% copper.
I sometime put a board in my wife's oven and heat the entire board. I now have a toaster oven I got used for $5.00. Heat everything up. If you only want to remove one part you can heat the entire board to below the milting point, then use the hot air gun to heat the one part you want off.

 

[Lightium]

I would measure the heat of the board as you apply heat to it.

 

[amateur_24]

My power boards have very thick coper. Many layers. Most layers are 90% copper.
I sometime put a board in my wife's oven and heat the entire board. I now have a toaster oven I got used for $5.00. Heat everything up. If you only want to remove one part you can heat the entire board to below the milting point, then use the hot air gun to heat the one part you want off.
View attachment 149844

How long do you preheat the board for ?1 min?
Or does it depend on the oven ?
I am really scared I'll kill the apu.

 

[schmitt trigger]

Hey Amateur 24,I have asked you a question that you didn’t bother to answer.
Taking a temperature measurement would take you less than a minute.
Now, if you don’t have a thermometer to measure it, please say so.

 

[ronsimpson]

How long do you preheat the board for ?1 min?

I am soldering the entire board. There are many YouTube videos on "reflow pc board solder using toaster oven". Watch the videos.
Here is a graph for soldering a board. It takes about 5 to 8 minutes.

Another picture. My oven naturally gives me a curve like my green arrow. They want the board to be at 150C for a while then up to the milting point for about 1 minute. Then I open up the door and let it cool off.

If you are only going to take one part off with a hot air gun, then heat the entire board up to 150C for 3-4 minutes maybe more if the board is thick, open up the door and heat that one part.

I have used two hot air guns. One bottom side heating a large area to 150 and one on top heating a small area to 250. (the air is hotter than 150)

I started using temperature probes but I found watching the solder milt tells me when we hit 220. That is all I care about.

 

[amateur_24]

But at the same time I refuse to be mocked by smd soldering. I am desperately wanting to learn and soldering.

Hey Amateur 24,I have asked you a question that you didn’t bother to answer.
Taking a temperature measurement would take you less than a minute.
Now, if you don’t have a thermometer to measure it, please say so.

Sorry I was waiting for my meter with a thermocouple to arrive. Am at the hospital with my dad I will measure the temp later. Maybe my soldering station is lying to me.

 

[schmitt trigger]

Thanks for your reply, hope your dad will speedily recover.

Back in topic; it would not be uncommon that even a brand new device is not functioning correctly.
The thermocouple will be a valuable addition not only for this issue, but for many more things in the future.